1. Field of the Invention
The present invention relates to a process for converting highly acidic waste water streams to a reusable clarified water effluent and an easily removable precipitate. More particularly the invention is directed to the treatment of phosphonic acid/phosphoric acid emulsions in water which results from methanol distillations.
2. Statement of the Prior Art
The art to which this invention relates is aware, inter alia, of the following U.S. Pat. Nos. 3,461,067; 3,480,144; 3,855,125; 3,423,309; and 3,694,356. The first of these describes a process for treating a sewage plant effluent by contacting same with metallic iron to convert organic substances and phosphate ions therein into water soluble iron salts and removing such salts from the purification system thereby obtaining decolorized water which is readily softened for industrial reuse. In U.S. Pat. No. 3,480,144, phosphates are removed from sewage streams treated by activated sludge by introducing aluminum or ferric ions into the aerating zone of the process. In U.S. Pat. No. 3,855,125, acids in industrial wastes are neutralized and removed by adding a core of lime having a shell of cracked calcium salt. In U.S. Pat. No. 3,423,309 is disclosed a process for removing phosphates from organic wastes by a combination of lime dosage, biological removal and metal salt dosing together with recirculation of precipitated chemical-containing sludges. In U.S. Pat. No. 3,694,356 is described a process for the purification of effluent from sewage treatment combined with the simultaneous purification of acidic mine drainage by combining the two streams in such proportions as to precipitate iron phosphates.
In coassigned U.S. patent application Ser. No. 532,337 filed Dec. 13, 1974 now abandoned, is described a method for chemically treating highly acid aqueous waste prior to biological treatment thereof to precipitate compounds which inhibit the subsequent biological degradation of the wastes. The method involves adding to the wastes an alkaline earth metal ion, or neutralizing with base followed by the addition of an alkaline earth metal ion. The preferred additive is calcium ion.